This paper proposed different approaches to enhance the performance of the Elliptic Curve Cryptography (ECC) algorithm. ECC is vulnerable to attacks by exploiting the public parameters of ECC to solve Discrete Logarithm Problem (DLP). Therefore, these public parameters should be selected safely to obviate all recognized attacks. This paper presents a new generator function to produce the domain parameters for creating the elliptic curve; a secure mechanism is used in the proposed function to avoid all possible known attacks that attempts to solve the Elliptic Curve Discrete Logarithm Problem (ECDLP). Moreover, an efficient algorithm has been proposed for choosing two base points from the curve in order to generate two subgroups in a secure manner. The purpose of the aforementioned algorithm is to offer more confidence for the user since it is not built upon a hidden impairment that it could be subsequently utilized to retrieve user's private key. The Elliptic Curve Diffie Hellman (ECDH) algorithm is implemented to exchange a session key between the communicating parties in a secure manner. Beside, a preprocessing operation is performed on the message to enhance the diffusion property and consequently leads to increase the strength against cryptanalysis attack. Finally, the dual encryption/decryption algorithm is implemented using different session keys in each stage of the encryption to boost immunity against any attack on the digital audio transmission. The gained results show the positive effect of the dual elliptic curve system in terms of speed and confidentiality without needing any extra time for encryption.

The Elliptic Curve Cryptography (ECC) algorithm meets the requirements for multimedia encryption since the encipher operation of the ECC algorithm is applied at points only and that offer significant computational advantages. The encoding/decoding operations for converting the text message into points on the curve and vice versa are not always considered a simple process. In this paper, a new mapping method has been investigated for converting the text message into a point on the curve or point to a text message in an efficient and secure manner; it depends on the repeated values in coordinate to establish a lookup table for encoding/decoding operations. The proposed method for mapping process is composed of various operations; firstly, the Exclusive OR and Circular Shift are performed on the message to enhance the diffusion property and that lead increasing the strength against cryptanalysis attack. Secondly, both parties agree on domain parameters for creating the elliptic curve and the mechanism to build the lookup table for encoding/decoding process. Thirdly, the base point is selected for generating all (x, y) pair points of the elliptic curve and extractcoordinate values to calculate the maximum value for and its frequency to create the lookup table. Finally, applying encoding/decoding operation for the message. The results of the proposed method are considered more efficient, secure and less time consuming compared with the ECC algorithm, besides it's suitable for preserving the confidentiality for real-time applications.

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The Advanced Encryption Standard (AES) is using in a large scale of applications that need to protect their data and information. A nonlinear substitution operation is the main factor of the AES cipher system strength. The S-Box component that used in AES is fixed, and not changeable. The purpose of the proposed approach is to use dual keys in encryption and decryption processes in SubByte transformation function. The first key generate multi random S-boxes depend on using multi keys that led to generate Sboxes provided that each one has its inverse associated with it, the second key is a random distribution of the S-boxes, the dual keys lead in increasing the complexity degree within the same delay time during the encryption and decryption processes in SubByte function. The results show that the present proposed algorithm has good cryptographic strength, with the added benefit that is resistant to linear and differential cryptanalysis, which require that the S-boxes be known beside the encryption key.